1. Field of the Invention
The present invention relates to medical functional elements, particularly in breathing masks, CPAP devices, breathing devices, hoses, sensors, moisturizers, and other medical/technical devices which are in contact with patients, wherein the new devices are configured to be easily cleanable.
2. Description of the Related Art
In order to connect two different materials, for example, for connecting a mask base body of hard plastic material with a soft mask bead of a soft elastomer, the so called two-component injection molding process is used. In this process, the hard component is configured in such a way that it can be manufactured by injection molding in a first manufacturing step. Subsequently, this component is placed into another mold, wherein the other mold still has hollow spaces when the component is placed therein. These hollow spaces are filled in a second step with a second material which in most cases is different from the first material. These components are then usually inseparably connected to each other by chemical, physical, or positively engaging connecting mechanisms.
An example of this two-component process is the use in medical breathing masks which are composed of a solid mask base body which provides in the mask the necessary stability and strength, and a mask bead which provides the sealing surface between mask and patient.
In a first step, the mask base body, usually of polycarbonate, polypropylene or polyamide (PC, PP, PA) is manufactured, and, in a second step, the mask bead, usually of silicon or thermoplastic elastomers (TPE) is injection molded onto the base body.
In plastics technology, as well as in other injection molding processes, it is attempted to dimension the wall thicknesses of a part to be injection molded uniformly. This prevents the formation of bubbles and sinks during the later cooling process. These bubbles and sinks become apparent in a transparent portion through the formation of bubbles in the material or by recessed surfaces in any type of material.
It is also known that an injection molded part can have a significantly better stability when it is provided with ribs.
In many medical/technical applications, moving and movable parts are necessary for carrying out certain functions. To be mentioned in this connection and examples may be locking elements, snap-in elements or other functional elements which, after being deflected, return automatically back into the original position if they are not prevented by a counterforce.
It is also known in the art that rigid materials are required for facilitating locking elements and snap-in elements. Rigid materials are brittle and, therefore, are very susceptible to breakage. This susceptibility to breakage is prevented if longer lever arms are constructed of the hard or brittle materials in order to distribute the forces over a large area when the elements are deflected.
In many cases, resilient elements are made of plastics materials which have a small thickness and are of oblong configuration.
In the attempt to prevent in injection molded parts with different wall thicknesses or transitions which are not smooth between two different wall thicknesses and to thereby prevent the formation of bubbles and sinks, frequently the surfaces of such a component are provided with a significant number of ribs and the resulting small radii, or are provided with corners and edges.
These dirt traps are very difficult to keep clean, particularly if patients have to frequently clean the medical articles, for examples masks, which are hygienic articles. In these systems which have been used in the past cleaning is possible only to a limited extent.
This effect is further increased by the formation of ribs at the actual casing. These dirt traps also occur if very fine locking elements, nap-in elements or other movable parts are present as functional elements in a device.
For example, lever arms are provided in closures which when one closure partner is inserted into the other closure partner, lever arms are provided which are deflected by a guide means provided at the other closure partner, until they are no longer guided and can once again snap back into their original position. The movement areas which are required for the deflection of the closure partners, do not have material and are usually constructed so has to be small and with fine surfaces, so that there are susceptible to dirt and are difficult to clean.
In order to be able to carry out the resilient effect, the resilient elements of plastic material require free movement space which is also very difficult to clean.